This invention relates to an apparatus and method for non-destructive testing of the strength of door frames, and appertains particularly to a mechanism designed to indicate frame strength by a method which measures the spreading effect of a known force against the frame.
Burglars often gain entry to a building or room in a building through a doorway by applying a spreading force to the frame of a door in the vicinity of the doorknob, until the latch bolt is freed from engagement with its corresponding strike plate in the door jamb. There has been little in the way of testing apparatus or procedures for checking entrance door security relative to the strength of the mounted frame.
While there are many prior art devices in general use for grading lumber that measure the stiffness or strength of the lumber, none of such devices would be suitable for testing the strength of door frames in the field. Therefore an efficient measurement device for checking a door frame's effective resistance to a spreading force would have obvious advantages and applications, particularly if it were portable.
Accordingly it is an object of the present invention to provide a device for testing the strength of door frames. It is a further object to provide a testing device and method which can be controlled and will not destroy or damage the door and door frame being tested.